Slip conveyors include longitudinally extending trays that are longitudinally vibrated (reciprocated) to transfer material along the conveyor. The longitudinal oscillation is rapid in one direction and slow in the other. The material is transported in the slow direction. Conveyors, including slip conveyors are described in U.S. Pat. No. 7,228,957 and U.S. patent application Ser. No. 11/108,052 (lodged on 14 Apr. 2005) and Ser. No. 11/263,762 (lodged on 31 Oct. 2205).
In the packaging industry, particularly the industry relating to the packaging of snack foods, product is delivered to a group of weighing machines, each of the weighing machines then communicates with an associated packaging machine such as the packaging machine described in U.S. Pat. No. 4,663,917. Conveyors, such as slip conveyors deliver the product to the weighing machines. A disadvantage of these known slip conveyors is that they cannot adapt to the varying demands of the different weighing and packaging machines.